CSE 4520/5520 Wireless Networks and Protocols
Homework 1
(Due 20th September, 2010)
In this homework we try to learn on formulating the real world problems into events and states. We analyze the process of cellular phone calls between two people. A subscriber in Dallas would like to call a mobile subscriber in Austin. There are two base stationss (one in Dallas and another in Austin) for forwarding the messages between mobile units. Derive event charts and state machines for a call setup, teardown, forward, and busy scenarios . Assume appropriate messages between the mobile users and base stations. Draw an event chart for all the transactions between mobile units and the BS. Make sure you cover as many error (i.e., unsuccessful) scenarios as possible. Next, develop state diagrams for each entity (caller, base station, and Callee). Include all the timers necessary for your work. See examples for event charts in the following references. We have discussed this problem in the class; so refer to the class notes for more details.
DO NOT copy a problem or a solution from these references or handouts (or matter of fact from any website). The states and transitions should be clearly defined. Pay special attention while picking up the states (e.g., states can be actions). Finally, you generate pseudo code for the state diagram. See the following references for the examples of pseudo code. In future, we will be writing the real code for this problem. Hence pay attention to details.
In your report, you include the following:
- Problem definition (3-6 sentences)
- Event chart with clear explanation for each event
- State diagram with states and transitions clearly defined
- Well commented pseudo code
- Conclusions
Grading:
- Event chart –15%
- State diagram – 30%
- Pseudo code –20%
- State diagram with forward and busy – 15%
- Report structure and readability 10%
- Conclusions – 10%
Some references:
http://homepages.feis.herts.ac.uk/~cs2_sdd/statecharts.html
http://www.microgold.com/version2/articles/article5/StampTrafficLight.html
http://www.objectmentor.com/courses/resources/articles/UMLSequenceDiagrams.pdf
ftp://ftp.rfc-editor.org/in-notes/rfc3215.txt